|  | 1.5 | Routing and the Different Classes of Routing Protocols
| 1.5.3 | Static and dynamic routes
Static routing is administered manually. A network administrator enters route into the router's configuration. The administrator must manually update this static route entry whenever a network topology change requires an update. Static routing reduces overhead because routing updates are not sent (in the case of RIP, every 30 seconds). Dynamic routing works differently. After the network administrator enters configuration commands to start dynamic routing, route knowledge is updated automatically by a routing process whenever new information is received from the network. Changes in dynamic knowledge are exchanged between routers as part of the update process. Static routing has several useful applications. It allows a network administrator to specify what is advertised about restricted partitions. For security reasons, the administrator can hide parts of a network. Dynamic routing tends to reveal everything known about a network. Additionally, when a network is accessible by only one path, a static route to the network can be sufficient. This type of partition is called a stub network. Configuring static routing to a stub network avoids the overhead of dynamic routing because routing updates are not sent.